Glass sheet processing systems for bending and/or tempering architectural glass or automotive glass include a furnace defining a heating chamber through which glass sheets are conveyed for heating and preparation for bending and/or tempering. One example of these systems is the horizontal oscillating glass tempering system disclosed by U.S. Pat. No. 3,994,711.
These systems typically include a roller conveyor for conveying the glass sheets, first from a supply table into the heating chamber, through the heating chamber, into and through a quench unit, and out of the quench and onto a take-out table from which the processed glass is removed.
The heating chambers in these systems typically include a plurality of independently controlled heating zones.
These systems also typically include a central control system capable of simultaneously monitoring various conditions throughout the system, including to the temperature within the furnace and the position of the glass sheets during processing. The central control system typically includes an operator interface or console which may be in the form of a teletype unit for inputting various data, such as desired temperature set points, into the central control system master computer.
One factor that is particularly critical in the efficient operation of these systems is the regulation of the heat within the furnace to insure the glass sheets are evenly heated to the desired temperature.
During installation and repair of the system, one or more temperature sensors, in the form of optical pyrometers are inserted at preselected locations in the system and connected to an analog strip chart recorder in order to create a strip chart. The strip chart is a graphic representation of the constant fluctuation in temperature on the surface of the glass sheets as they pass the preselected location.
These strip charts may be analyzed by trained personnel to provide information about the temperature fluctuation along the surface of the moving glass sheet and, therefore, the efficiency of the heating chamber. However, the graphic analog information disclosed by the strip charts is voluminous and is not translated into data recognizable to the operator--such as actual temperature values, and is therefore of limited use as a dynamic monitoring or feedback tool for the operator.
Also, the continuous stream of signals recorded by the strip chart recorder includes signals corresponding to temperatures taken at points between glass sheets. In addition, the continuous nature of the output does not allow the operator to isolate temperature profiles for individual glass sheets of varying sizes.
It is one object of the present invention to provide an automatic temperature monitoring and control system for use in connection with a glass sheet processing system which provides nearly instantaneous information to the operator in the form of a temperature profile of the surface temperatures along the direction of conveyance of a glass sheet conveyed through the system.
It is also an object of the present invention to provide a automatic temperature monitoring and control system for use in connection with a glass sheet processing system which provides nearly instantaneous information to the operator in the form of a temperature profile of the surface temperatures along the direction of conveyance of glass sheets for a single load of glass sheets conveyed through the system.
It is also an object of the present invention to provide an automatic temperature monitoring and control system which allows the operator to program in selected values for one or more variables utilized by the system. In particular, it is an object of the present invention to provide a system which allows the operator to vary the values of one or more variables in order to insure that each of the temperature profiles displayed by the system represents a profile along the length of a glass sheet or load of glass sheets for glass sheets and loads of varying length.
It is also an object of the present invention to provide an automatic temperature monitoring and control system which provides nearly instantaneous statistical information in the form of average, maximum, or minimum temperatures or the like, for each load and/or for each sheet in a load of glass sheets being conveyed through the glass processing system.
It is also an object of the present invention to provide an automatic temperature monitoring and control system which provides nearly instantaneous statistical information for each glass sheet being conveyed through the glass processing system along with a display of like statistical information for a previous number of glass sheets.
It is also an object of the present invention to provide an automatic temperature monitoring and control system which provides nearly instantaneous statistical information for each load of glass sheets being conveyed through the glass processing system along with a display of like statistical information for a number of previous loads of glass sheets.
It is a further object of the present invention to provide an automatic temperature monitoring and control system which monitors the temperature on the surface of glass for the entire length of a glass sheet traveling past a selected point in the system, analyses the temperatures, and automatically adjusts the power to one or more of the heating zones about the length of the heating chamber as a function of the analyzed temperature data.